In general, an LCD device displays image information using liquid crystal. In order to display image information, an LCD device includes a light supplying part that generates light needed to display image information, an optical part that allows light supplied from the light supplying part to have uniform brightness and a liquid crystal controlling part that controls liquid crystal.
The LCD device employs a CCFL (Cold Cathode Fluorescent Lamp) having characteristics, for example, such as a long life, a white light and a small amount of heat generation as a light supplying part.
The optical part plays a role that makes brightness of light emitted from the CCFL to be uniform. The optical part may include various optical sheets depending on a type of the LCD device.
The optical sheet includes a diffusion sheet that allows brightness distribution of light to be uniform by diffusing light emitted from the CCFL and a prism sheet that collects light diffused by the diffusion sheet.
The optical sheet may include a light guide plate. Light guide plate changes optical property, for example, such as linearity of light emitted from the CCFL into a form of surface light.
The liquid crystal controlling part controls liquid crystal in a unit of pixel so as to control transmittance of light processed in the optical part, thereby displaying image information.
The light supplying part, the optical part and the liquid crystal controlling part play important roles in a display operation of the LCD device. Especially, the optical part has remarkable influence upon display quality of image information.
The diffusion sheet and the prism sheet of the optical part are fixed to a frame of the LCD device using a double sided tape or a hole formed thereon and a boss formed at the frame of the LCD device.
However, the optical part may be easily expanded with heat because the optical part is fabricated with a thin sheet made of synthetic resin. Particularly, in case that the optical part securely fixed to the frame by double sided tape is expanded, the optical part may be easily wrinkled because there is no extra space in the frame of the LCD device. As a result, image information may not be normally displayed on a screen.
For this reason, a method that allows the optical part received in the frame of the LCD device to be moved has been used in this age. However, in case of fixing the optical part to the frame such that it may be moved in the frame, the optical part may collide with the liquid crystal controlling part adjacent to the optical part when impact is applied to the frame of the LCD device. As a result, the optical part and the liquid crystal controlling part may be fatally damaged by scratch therebetween so that display quality is deteriorated.